Traverse mechanism



Dec. 13, 1960 A. EDELMAN EIAL TRAVERSE MECHANISM 5 Sheets-Sheet 1 FiledFeb. 23. 1955 M m. m2 W :22 V IU H NZNMM y R m m I? g. n a am 1 3 10 YililiEEHRHHLHt l Dec. 13, 1960 Filed Feb. 23. 1955 A. EDELMAN ETALTRAVERSE MECHANISM 3 Sheets-Sheet 2 INVENTOR'S' ABP/U/AM fan/141v By650265 14 0540 Dec. 13, 1960 A. EDELMAN ETAL 2,964,260

TRAVERSE MECHANISM Filed Feb. 25. 1955 3 Sheets-Sheet 3 I N V EN TORSABRAHAM DELM 4/Y @5006: Aasaov A FOP/V675 United States Patent TRAVERSEMECHANISM Abraham Edelman and George E. Koslow, New York, N.Y.,assignors to Celanese Corporation of America, New York, N.Y., acorporation of Delaware Filed Feb. 23, 1955, Ser. No. 489,984

9 Claims. (Cl. 242-158) This invention relates to a traverse mechanismand relates more particularly to a high speed traverse mechanism for ayarn winding machine.

Traverse mechanisms of many types have been developed for guidingfilamentary material, which may be a textile yarn or the like, onto atake-up package. Mechanically actuated traverse mechanisms are quitesatisfactory at relatively low traverse speeds and rates. However, asthe traverse speed, the linear speed of the traverse element, or thetraverse rate, the frequency at which the traverse element is reversed,increase, mechanical traverse mechanisms are no longer satisfactoryowing to their high power requirements and the rapid wear that occurs atsuch speeds or rates. To overcome these difficulties, there have beendeveloped pneumatically and electromagnetically actuated traversemechanisms that can be operated at higher traverse speeds and rates thanare feasible with conventional mechanically actuated traversemechanisms. However, these prior pneumatically and electrically actuatedtraverse mechanisms suffer from a number of drawbacks, including a lackof flexibility as to operating speed, an inability to control thedelivery of power to the traverse element throughout the entire lengthof its stroke and poor operating characteristics when the traverse pathexceeds a given length.

It is an important object of this invention to provide a traversemechanism which will be free from the foregoing and other difficulties.

A further object of this invention is to provide a high speed traversemechanism actuated by a linear polyphase motor.

Other objects of this invention, together with certain details ofconstruction and combinations of parts, will be apparent from thefollowing detailed description and claims.

According to the present invention there is provided a traversemechanism for a yarn winding machine comprising a linear polyphase motorto the armature of which there is secured a yarn guide. The polyphasemotor includes a plurality of coils that are linearly disposed and areconnected to a polyphase power supply in such a manner that the saidcoils will produce a moving magnetic field in which the armature ispositioned and by which it is moved. Connected to said armature is theguide through which filamentary material is drawn whereby the movementof the armature will act to move the filamentary material through itstraverse stroke. Means are also provided for periodically reversing theconnections to said coils whereby the direction of movement of themagnetic field will be reversed, causing the armature and the guideconnected thereto to move in the opposite direction.

While the foregoing arrangement permits high traverse speeds and ratesto be achieved, even better results can be obtained if there areprovided means at each end of the traverse stroke for converting thekinetic energy of movement of the armature and the parts connectedthereto into potential energy and delivering said energy 2,964,260Patented Dec. 13, 1960 back to the armature as it starts moving in theopposite direction. Such means, may, for example, comprise a springpositioned in the path of and adapted to be compressed by the armature.In this way the amount of energy that must be supplied to the armatureis held at a minimum and the efliciency of operation is increasedsignificantly.

It is not feasible to start the apparatus of this invention at thedesired speed owing to the inertia of the armature. Accordingly, thereare provided auxiliary starting means for reversing the direction ofmovement of the magnetic field at a slow rate at the outset and forincreasing this rate gradually until the armature is moving at thedesired speed. Once this has occurred, such auxiliary starting means maybe disconnected from the apparatus.

A preferred embodiment of this invention is shown in the accompanyingdrawings wherein Fig. l is a plan view of the traverse mechanism itselfwith certain parts broken away,

Fig. 2 is a front elevation of the traverse mechanism itself withcertain parts broken away,

Fig. 3 is a cross-sectional view of the traverse mechanism taken alongthe line 3-3 in Fig. 1 in the direction of the arrows, and showing inaddition the position of the traverse mechanism in a yarn windingmachine,

Fig. 4 is a detail cross-sectional view taken along the line 4-4 in Fig.1 in the direction of the arrows,

Fig. 5 is a detail cross-sectional view taken along the line 55 in Fig.1 in the direction of the arrows, and

Fig. 6 is a circuit diagram of the electrical connections of thetraverse mechanism.

Referring now to the drawings, the reference numeral 11 in Fig. 3designates a yarn which is drawn from any suitable source such as aspinning metier (not shown) and directed by means of a yarn guide 12onto a take-up roll 14 which is driven at a constant peripheral speed bymeans of a feed roll 13 in frictional contact therewith. The yarn guide12 is reciprocatetl to form on the take-up roll 14 a yarn package havingthe desired wind by means of a traverse mechanism, indicated generallyby reference numeral 15, which traverse mechanism is fastened by bolts16 to the frame 17 of the winding machine.

The traverse mechanism 15 comprises an upper housing 18 and a lowerhousing 19 that are spaced from one another by means of separators 21positioned between the ends thereof. The upper housing 18, the lowerhousing 19 and the separators 21 are held together as a unit by means ofscrews 22 that extend through the upper housing and the separators intothreaded engagement with apertures 23 in the lower housing. There arepositioned in the upper housing 18 and in the lower housing 19 aplurality of E-shaped laminations 24 around the legs of which are coils25, and the whole is impregnated with a suitable potting compound 26.Secured to the legs of the laminations 24 are pole pieces, indicatedgenerally by reference numeral 27, comprising a plurality of bundles oflaminations 28, Figs. 1 and 2, extending at right angles to thelaminations 24 and positioned to abut the legs of the said laminations24. Pole faces 29 positioned between the bundles of laminations 28define a plurality of gaps 31. The laminations 28 and the pole faces 29are held in place by means of rods 32 that extend through apertures insaid members, while the rods 32 are themselves held in place by poleclamps 33 that engage the said rods and have screws 34 extending throughthe ends thereof into threaded apertures 35 in the housing 18 and 19.

As shown most clearly in Fig. 2 of the drawings, the pole pieces 27positioned in the upper housing 18 are spaced from the pole pieces 27positioned in the lower housing 19 and the said pole pieces definebetween them a narrow elongated passageway 36. Also, as shown in Fig. 2of the drawings, the pole pieces 27 are so positioned in the upperhousing 18 that each of said pole pieces is midway between a pair ofpole pieces 27 in the lower housing 19. In this way, there is attainedbetween the said pole pieces a strong magnetic field in the passageway36. Positioned in the passageway 36 is an armature comprising agenerally rectangular aluminum slider plate 37 to the upper edge ofwhich there is secured, by means of screws 38, a pair of flat bearingblocks 39 that are supported slideably between elongated bearing members41 fastened to the lower housing 19 with screws 42. To the lower edge ofthe slider plate 37 there is fastened, by means of screws 43, a slider44 that is mounted for longitudinal movement on a rod 45. The ends ofthe slider 44 are equipped with bushings 46 that engage the rod 45 so asto minimize friction therebetween. To support the rod 45, there areprovided V-blocks 47, Fig. 5, that are held in place by means of bolts48 that extend through the rod 45 and the V-blocks 47 into threadedengagement with the lower housing 19. A yarn guide holder 49 isfastened, by means of screws 51, to the slider 44 and carries at itsends two yarn guides 12, Fig. 1. It is to be understood that the numberof yarn guides 12 may be greater or less than that specifically shown,depending on the spacing between successive yarns, the desired speed andrate of traverse, and the like. Encircling the ends of the rod 45 areweak springs 52, one end of each of which is engaged under the bolt 48,and the other end of each of which abuts an oil-saturated felt washer 53mounted slideably on the rod 45. The washers 53 are adapted to beengaged by the slider 44 towards the end of its traverse stroke therebycompressing the spring 52. The spring 52 will expand when the slider 44begins to move in the opposite direction and will move for a certaindistance past its point of rest, thereby applying a film of oil to therod 45 and effectively lubricating the said rod.

There are provided at each end of the traverse stroke bumpers, indicatedgenerally by reference numeral 54, that are fastened by means of screws55 to brackets -56 clamped in place by bolts 57 extending through a slot58 in the lower housing 19 and entering into threaded engagement withstraps 59. The bumpers 54 each comprise a tubular housing 60 having atone end thereof an inwardly extending flange 61. Positioned in thehousing 60 is a spring 62 one end of which bears against a washer 63that abuts the bracket 56 and the other end of which abuts against awasher 64 that abuts the flange 61. The washer 64 is provided with aprojection 65 that extends through the opening formed by the flange 61.The bumpers 54 are positioned so that the edge of the slider plate 37will strike one of the projections 65 at each end of the traversestroke. The impact of the slider plate 37 will compress the spring 62whereby the kinetic energy of motion of the slider plate 37 and theparts connected thereto will be converted into potential energy in thecompressed spring. The spring 62 will then expand moving the sliderplate 37 in the opposite direction and providing a considerable portionof the energy needed to start the said slider plate through its traversestroke. In this way, the amount of energy that must be supplied to theslider plate 37 is held to a minimum and the speed and rate of traversemay be raised to high levels without running into difiiculty. Thesprings 62, as pointed out above, are so designed that they will absorbas potential energy of compression substantially all the kinetic energyof motion of the slider plate 37 and will tend to bring said sliderplate to a halt. However, if complete reliance were placed on thesprings 62 to halt the slider plate 37, the precise point at which thesaid slider plate would halt would vary depending upon the speed withwhich the slider plate 37 is moving under any given set of conditions.This would result in an undesirable change in the length of the traversestroke. To avoid such difiiculty, the spring 62 is so designed that theimpact of the slider plate 37 will compress the spring 62 until theslider plate 37 strikes the end of the housing 60 itself which will, ofcourse, stop the movement of the slider plate 37 at a fixed point. Inthis way, the length of the traverse stroke will be fixed. By changingthe position of the bumpers 54 the length of the traverse stroke can bealtered at will.

The traverse mechanism is equipped with conduits 66 and 67 through whichthe electrical wiring for the coils 25 is brought to the upper housing18 and the lower housing 19, respectively.

To guard against accidental contact with the moving parts of thetraverse mechanism, there is provided a shield 68, Fig. 3, that isfastened to the upper housing 18 by means of screws 69.

The electrical circuit of the traverse mechanism is shown in detail inFig. 6 of the drawings and comprises terminals 70 to which three-phasealternating current is supplied. Connected to the terminals 70 through aswitch 71 is a three-phase autotransformer 72, the output of which isconnected to the primary winding 73 of a transformer 74 having asecondary winding 75 that is connected to the coils 25 through aswitching circuit that will be described in greater detail below. Thecoils 25 are connected to the transformer 74 in such a manner that amoving magnetic field will be created in the passageway 36 and willprovide the necessary force to urge the slider plate 37 from one end tothe other end of its traverse stroke. For example, the coils 25 are soconnected to the transformer 74 that the first coil in the upper housing18, Fig. 2, designated A, is connected to phase 1, the second coil,designated B, is connected to phase 2, and the third coil, designated C,is connected to phase 3. This cycle of connections is repeated for allthe remaining coils '25 in the upper housing 18. The coils 25 in thelower housing 19 are connected to the transformer 74 in a similar cyclicmanner. To obtain a magnetic flux of maximum intensity, the coils 25 inthe lower housing 19 are connected to the transformer 74 in such amanner that each coil in said lower housing is connected to a phaseother than that to which are connected the coils 25 in the upper housing18 between which it is located. That is, coil D is connected to phase 3,coil E is connected to phase 1, etc. In addition, the connections to thecoils 25 are made in such a manner that the magnetic fluxes will tend toreinforce one another. For example, when the magnetic flux is coming outfrom coils A and B, it should be going in on coil D, etc.

The moving magnetic field produced by the coils 25 will drive the sliderplate 37 which acts as the armature, and all the elements connectedthereto from one end to the other end of the traverse stroke. To reversethe direction in which the magnetic field produced by the coils 25moves, there is provided a switching circuit comprising a compound woundmotor 76 to which direct current is supplied from alternating currentterminals 77 through a switch 78 and a rectifier bridge 79. The motor 76drives a commutator section 81 that includes a slip ring 82 connected toone terminal of the output of transformer 74, and a slip ring 83connected to another terminal of the output of the said transformer. Thecommutator section 81 also includes a commutator 84 having two equalsections, one of which is connected to the slip ring 82 and the other ofwhich is connected to the slip ring 84. The output from the commutator84 is connected to the coils 25. As shown in Fig. 6 of the drawings, oneterminal of the output of the transformer 74 is connected directly tothe coils 25, whereas the remaining two output terminals of thetransformer 74 are connected to the coils 25 through the commutator 84so that such conuections are periodically reversed. When such reversaloccurs, the direction of movement of the magnetic field produced by thecoils 25 will also reverse and drive the slider plate 37 in the oppositedirection. The frequency with which such reversal takes place may beregulated by adjusting the rheostat 85 to bring the motor 76 to thedesired speed. In addition, the transformer 72 may be adjusted toregulate the voltage applied to the coils 25 so that the strength of themagnetic fields produced by said coils and the forces acting on theslider plate 37 and the speed with which such plate moves may be varied.It has been found that the most reliable operation is secured when theadjustments are made in such a manner that the slider plate 37 reachesthe end of its traverse stroke and is beginning to move in the oppositedirection under the urging of the spring 62 before the connections tothe coils 25 are reversed. With this arrangement there is no tendencyfor stalling to occur even when excessive loads are applied momentarilyto the traverse mechanism.

While the traverse mechanism will operate successfully in the mannerdescribed above, once it has been started,-it will not start of its ownaccord owing to the inability of the moving parts going in one directionto come up to operating speed before the commutator 84 reverses thedirection of movement of the magnetic field. A separate circuit isaccordingly provided to start the traverse mechanism. The startingcircuit comprises a compound wound motor 86 which is connected to therectifier bridge 79 through a circuit including a starting button 87which when closed completes the circuit from the rectifier bridge 79 andenergizes holding coil 88 and coil 89 of a relay 91. When holding coil88 is energized, it closes a quick-operating holding contact 92connected in parallel with the starting button 87 so that current willcontinue to flow through coils 88 and 89 even after the said startingbutton is released. Coil 89, when energized, closes contacts 93 and 94,and moves contacts 95 and 96 from an up to a down position. Closing ofcontact 93 completes the circuit from the rectifier bridge 79 to thestarting motor 86 so that said motor will begin to turn, driving acommutator section 97 to which it is connected. The commutator section97 is identical to and is connected in parallel to the commutatorsection 81. Thus, the commutator section 97 includes slip rings 98 and99 that are connected in parallel to the slip rings 82 and 83, and alsoincludes a commutator 101 having two equal sections one of which isconnected to the slip ring 98 and the other of which is connected to theslip ring 99. The output of the commutator 101 is connected to the lowerpoints of contacts 95 and 96 so that when the relay 91 is energized andthe said contacts are in their down position, current is supplied to thecoils 25 through the commutator section 97.

The starting motor 86 is so designed that it will come up to speedslowly. As a result, the direction of motion of the magnetic fieldproduced by the coils 25 will, at the outset, change at a slow frequencythereby permitting the slider plate 37 to come up to operating speedgradually. When the slider plate 37 has reached operating speed, controlof the supply of current to the coils 25 is shifted from the startingmotor 86 to the motor 76. To effect such changeover automatically, thereis provided a time delay relay 102 having a normally closed contact 103that is connected in series with the holding coil 88. The relay 102 isenergized simultaneously with the starting motor 86 by the closing ofthe contact 94. After a sufiicient period has elapsed, the relay 102will open the contact 103 and hold the same open as long as the contact94 remains closed. When the control of current to the coils 25 isswitched from the starting motor 86 to the motor 76, care must be takenthat at such time the commutator section 81 will supply current to thesaid coils. having the same phase relationship as that which has beensupplied by the commutator section 97, otherwise the movement of theslider plate 37 may stop. To insure that such phase relationship willexist, there is provided in the commutator section 81 a slip ring 104that is connectedlto a commutator 105 having a single opening therein.The slip ring 104 and the commutator 105 are connected in parallel withthe contact 103. There is also provided in the commutator section 97, aslip ring 106 connected to a commutator 107 having a single openingtherein. The slip ring 106 and the commutator 107 are also connected inparallel with the contact 103. When the contact 103 opens, current willcontinue to flow through the coil 88 until the commutator sections 81and 97 come into alignment as shown in the drawings, at which time thephase connections to said commutator sections will be identical. Then,the connections through the commutators 105 and 107 will be openedsimultaneously, de-energizing the coil 88 of the relay 91 whereby thecontact 92 will release quickly cutting olf the current to the coil 89and thereby opening the contacts 93 and 94, and moving the contacts 95and 96 to the down position. This will interrupt supply of current tothe starting motor 86 and the relay 102, and will shift the control ofthe flow of current to the coils 25 to the motor 76. It is to be notedthat with the arrangement of the commutator sections 81 and 97 shown inthe drawings, such shifting of control will occur at the time that nocurrent is flowing through either of the commutator sections to the saidcoils. To avoid the possibility that the traverse mechanism will stop atthe time the control is shifted from the starting motor 86 to the motor76, the full speed of the starting motor 86 is set, by means of therheostat 111, at a level somewhat higher than that of the motor 76. Thisdifference in speed insures that the commutator sections 81 and 97 willnot remain out of synchronism for an extended time. It also insuresthat, if the speed of the slider plate 37 drops momentarily during theshifting over, it will not drop so low that continued operation will beimpossible.

One of the difficulties encountered in the winding of filamentarymaterials into packages is known as ribboning and occurs when thegeometry of the Winding operation is such that successive turns of thefilamentary material are positioned substantially on top of one anotherto form a ridge or ribbon. A package containing such a ribbon exhibits atendency for the yarn windings to shift relative to one another. Such apackage is also diflicult to unwind at a high speed. To prevent suchribboning, optional means are provided for varying the speed of themotor 76 from time to time so as to change the geometry of the windingoperation and displace the successive turns of the winding from oneanother. Such speed changing means includes a double-pole doublethrowswitch 109 which is shown in a position where no change in speed iseffected. However, when the switch is thrown to the left, it willconnect in series with the rheostat the rheostat 111. It will alsoenergize a timer 112 that closes and opens a contact 113 at any desiredrate, which contact 113 is connected to short out the rheostat 111 whenclosed. When the contact 113 is closed the motor 76 and the slider plate37 will operate at a speed determined by the rheostat 85. On the otherhand, when the contact 113 is open, the motor 76 and the slider plate 37will operate at a lower speed.

To operate the traverse mechanism, the switches 71 and 78 are closed.This will supply power to the coils 25 and the motor 76 whereby the saidmotor will come up to speed, but the slider plate 37 will not move.Then, the starting button is closed momentarily whereby the startingcircuit will bring the slider plate 37 up to speed and will cut off,leaving the traverse mechanism operating at the proper speed.

While the drawings show only a single traverse mechanism connected tothe electrical circuit, it should be understood that normally a numberof such mechanisms will be connected in parallel. In such case, suitableswitch means may be provided for connecting one traverse mechanism at atime to the starting motor 86 so that said traverse mechanisms may bestarted up independently, or so that one of the traverse mechanisms maybe started up while the others are operating. For example, the coils 25of a second traverse mechanism may be connected to a double-poledouble-throw switch that is wired in parallel to the contacts 95 and 96.

While each of the coils 25 may be identical, it may also be desirable touse different coils at difierent points along the traverse path. In thisway, the supply of energy to the slider plate 37 may be varied frompoint to point so that the speed of said plate may be adjusted in anydesired manner. The same effect may be attained, for example, byinserting resistances in series with selected coils 25.

It is to be understood that the foregoing detailed description is merelygiven by way of illustration and that many variations may be madetherein without departing from the spirit of our invention.

Having described our invention, what we desire to secure by LettersPatent is:

1. In a winding machine, a traverse mechanism comprising means forproducing a moving magnetic field, an armature positioned in said fieldfor movement thereby, means for reversing the direction of movement ofthe magnetic field continuously and repeatedly so as to reverse thedirection of movement of the armature, means positioned in the path ofmovement of the armature for converting the kinetic energy of motion ofthe armature moving in one direction into potential energy and forreturning said potential energy to the armature to move it in theoppostie direction, said means for reversing the direction of movementof the magnetic field acting to reverse the direction of movement ofsaid field after the direction of movement of the armature has beenreversed by said energy converting means, and guide means for afilamentary material connected to said armature.

2. A reciprocating mechanism comprising means for producing a movingmagnetic field, an armature positioned in said magnetic field formovement thereby, control means for reversing the direction of movementof the magnetic field at a predetermined rate so as to reverse thedirection of movement of said armature at said rate, and starting meansto reverse the direction of movement of the magnetic field initially ata lower rate than said predetermined rate and to increase gradually saidrate.

3. A reciprocating mechanism comprising means for producing a movingmagnetic field, an armature positioned in said magnetic field formovement thereby, control means for reversing the direction of movementof the magnetic field at a predetermined rate so as to reverse thedirection of movement of said armature at said rate, starting means toreverse the direction of movement of the magnetic field initially at alower rate than said predetermined rate and to increase gradually saidrate until it is greater than said predetermined rate, and means forshifting the reversal of said magnetic field from said starting means tosaid control means.

4. A reciprocating mechanism comprising a plurality of linearly disposedcoils adapted to produce a moving magnetic field, an armature positionedin said field for movement thereby, switching means for reversing. theconnections to said coils to reverse the direction of movement of themagnetic field at a predetermined rate so as to reverse the direction ofmovement of the armature at said rate, and auxiliary switching means forstarting to reverse the connections to said coils to reverse thedirection of movement of the magnetic field initially at a lower ratethan said predetermined rate and to increase gradually said rate.

5. A reciprocating mechanism comprising a plurality of linearly disposedcoils adapted to produce a moving magnetic field, an armature positionedin said fieldfor movement thereby, switching means for reversingftheconnections to said coils to reverse the direction of movement of themagnetic field at a predetermined rate so as to reverse the direction ofmovement of the armature at said rate, auxiliary switching means forstarting to reverse the connections to said coils to reverse thedirection of movement of the magnetic field initially at a lower ratethan said predetermined rate and to increase gradually said rate untilit is greater than said predetermined rate, and means for shifting thereversal of said magnetic field from said auxiliary switching means tosaid first-mentioned switching means when said means are in phase withone another.

6. A reciprocating mechanism comprising a plurality of linearly disposedcoils adapted to produce a moving magnetic field, an armature positionedin said field for movement thereby, switching means for reversing theconnections to said coils to reverse the direction of movement of themagnetic field at a predetermined rate so as to reverse the direction ofmovement of the armature at said rate, auxiliary switching means forstarting to reverse the connections to said coils to reverse thedirection of movement of the magnetic field initially at a lower ratethan said predetermined rate and to increase gradually said rate untilit is greater than said predetermined rate, means for shifting thereversal of said magnetic field from said auxiliary switching means tosaid first-mentioned switching means when said means are in phase withone another, and springs positioned in the path of movement of thearmature and adapted to be struck thereby for converting the kineticenergy of motion of the armature in one direction into potential energyof compression and for returning said potential energy to the armatureto move it in the opposite direction, said switching means acting toreverse the direction of movement of the magnetic field after thedirection of movement of the armature has been reversed by the springs.

7. A reciprocating mechanism comprising a plurality of linearly disposedcoils adapted to produce a moving magnetic field, an armature positionedin said field for movement thereby, switching means for reversing theconnections to said coils to reverse the direction of movement of themagnetic field at a predetermined rate so as to reverse the direction ofmovement of the armature at said rate, means for varying the rate atwhich such reversal takes place, auxiliary switching means for startingto reverse the connections to said coils to reverse the direction ofmovement of the magnetic field initially at a lower rate than saidpredetermined rate and to increase gradually said rate until it isgreater than said predetermined rate, means for shifting the reversal ofsaid magnetic field from said auxiliary switching means to saidfirst-mentioned switching means when said means are in phase with oneanother, springs positioned in the path of movement of the armature andadapted to be struck thereby for converting the kinetic energy of motionof the armature in one direction into potential energy of compressionand for returning said potential energy to the armature to move it inthe opposite direction, said switching means acting to reverse thedirection of movement of the magnetic field after the direction ofmovement of the armature has been reversed by the springs, and stopspositioned in the path of movement of the armature and adapted to bestruck thereby for stopping the movement of the armature at a definiteposition.

8. A mechanism for producing reciprocating motion comprising means forproducing a moving magnetic field, an armature positioned in said fieldfor movement thereby, means for reversing the direction of movement ofthe magnetic field so as to reverse the direction of movement of thearmature, and means positioned in the path of movement of the armaturefor converting the kinetic energy of motion of the armature moving inone direction into potential energy and for returning said potentialenergy to the armature to move it in the opposite direction, said meansfor reversing the direction of movement of the magnetic field acting toreverse the direction of movement of said field after the direction ofmovement of the armature has been reversed by said energy convertingmeans.

9. A mechanism for producing reciprocating motion comprising means forproducing a moving magnetic field including a plurality of pole-piecesin opposed, staggered relation, an armature positioned in said field formovement thereby, means for reversing the direction of movement of themagnetic field so as to reverse the direction of movement of thearmature, and means positioned in the path of movement of the armaturefor converting the kinetic energy of motion of the armature moving inone direction into potential energy and for returning said potentialenergy to the armature to move it in the opposite direction, said meansfor reversing the direction of movement of the magnetic field acting toreverse the direction of movement of said field after the direction 10of movement of the armature has been reversed by said energy convertingmeans.

References Cited in the file of this patent UNITED STATES PATENTS

